A KINETIC-STUDY OF THE KUDZU (PUERARIA-LOBATA) RETTING PROCESS

Kudzu (Pueraria lobata) is an unwanted plant which grows wild in the S outhern United States. It was introduced in the United States to contr ol soil erosion during the 1930's. Kudzu vines provide high quality ba st fiber that has been used for over 750 years in the Orient and still finds limited use in China in handwoven textiles. The natural fiber e xtracted from the kudzu vines may have potential economical value eith er alone or in blends with polyester to make a commercial fabric woven on power looms. To extract the desired fiber from the raw kudzu vines , a modified natural retting process has been employed. A simple scrap e test has been used to quantitatively determine the degree of retting , i.e. the removal rate of the outer sheath covering the fibre in the kudzu vines. The decomposition of the outer sheath of kudzu vines, as measured by the scrape test, has been analyzed to calculate two lumped enzyme kinetic constants, K-m/S-o and eta V/S-o, where eta is the eff ectiveness factor; S-o, the initial substrate concentration; K-m, the Michaelis constant, and V is the maximum product rate. The scrape test has been quantified by the use of the Desheathing Index (D.I.), which is a dimensionless group derived from the nunber of strokes in the sc rape test. The solid vine in water (retting) data have been compared t o previously collected solid state fermentation (solid vines in soil) data. The specific stress and its relation with D.I. of kudzu fibers i n different seasons have also been discussed. It is argued that the Sp ring kudzu vines provide the strongest fibers, but they have a low eff ectiveness factor.